It runs headfirst into the fourth wall, falls down, sees those little cartoon birds circle its head, blacks out for a bit, picks itself up, grabs one of those jogging trampolines and uses it to bounce just high enough above the fourth wall so you can see its grinning, winking mug while it screams, “Hey, look at me! I’m a sequel that’s all about how sequels cost twice as much as the original but they’re never quite as good! How awesome is that?”

And then it throws up.

After an extended break, officers Schmidt (Jonah Hill) and Jenko (Channing Tatum) are reassigned to Jump Street by Deputy Chief Hardy (Nick Offerman), the movie’s voice of meta reason. In the original, Hardy explained how reviving the canceled Jump Street program just proved that everyone had run out of new ideas. Here, he lectures the duo about how things are always worse the second time around. (In case that’s too subtle, there’s a running joke, kicking off long before the movie’s end, about how they’ve already used up their budget.)

Since their last case, the abandoned Aroma of Christ Church building, located at 21 Jump Street, has been purchased. Thankfully, there’s a larger abandoned church, the Resurrection of the Holy Spectacle, right across the street for Schmidt, Jenko and Captain Dickson (Ice Cube) to call home.

Just like in the first movie, there’s a dangerous new synthetic drug that makes people freak out and die, so Schmidt and Jenko go undercover at Metro City State University to find the supplier. As Dickson tells them, often, “It’s the same case. Do the same thing.”

Jenko falls in with the star quarterback (Wyatt Russell) and his fraternity brothers. Schmidt cozies up to the arts students through Maya (Amber Stevens), who lived next to the dead girl. But, for the most part, they barely bother with their investigation into the drug WHYPHY (Work Hard? Yes! Play Hard? Yes!), which seems to exist solely so Jenko can confuse it with Wi-Fi.

Honestly, “22 Jump Street” doesn’t really need much of an investigation. It’s all just an excuse for Hill and Tatum to showcase their remarkable chemistry. Having said that, though, the plot isn’t just thin, it’s borderline anorexic.

The villain (Peter Stormare) doesn’t even make sense as he and his gang go from dealing in exotic animals to being wrapped up in the WHYPHY ring. He’s really just there because Schmidt and Jenko need someone to shoot at them.

Things also go on a bit too long. Just when you’ve enjoyed some solid laughs and it feels like everything is wrapping up, you remember the ads and realize, “Oh, dear lord, they still haven’t gone to spring break!”

And some of the scenes, including almost everything related to football and the fraternity, fall remarkably flat.

Yet there are so many moments of borderline genius — credited to Michael Bacall, who wrote the original, newcomer Oren Uziel and “Grudge Match’s” Rodney Rothman — that they more than make up for the slack moments. Take the gag in which the most obvious suspect is revealed to have a tattoo of the mascot of his high school team, the Plain View Red Herrings. To steal from Larry the Cable Guy, I don’t care who you are, that’s funny.

Like its predecessor, “22 Jump Street” was directed by Phil Lord and Christopher Miller, who, along with their work helming “The Lego Movie,” have become masters of exceeding dangerously low expectations.

Some of the biggest laughs come from Maya’s roommate, Mercedes (Jillian Bell of “Workaholics”). When she isn’t riffing improv-style on how old Schmidt looks — “You’ve got 99 problems, but being young ain’t one” — she’s brawling with him. It’s always tricky to ask audiences to laugh at a man and woman trading punches, but this is among the silliest, weirdest fights you’ll ever see.

And as Dickson, Ice Cube again makes for a far more entertaining cop than he did in “Ride Along.”

Tatum continues to come off like a hunky, eager-to-please puppy, bounding about the set. He’s even game for a “White House Down” dig when Jenko is told his idea of joining the Secret Service to protect the president sounds horrible.

In a refreshing change, the marketing team kept some of the best jokes from being spoiled by the trailers. You’ll certainly laugh. A lot. (Not nearly as much as the guy sitting behind me, but I think he had some type of disorder.)

Be sure to stick around for the closing credits, which display more creativity than the entirety of many summer movies.

Those scenes will leave you longing for the next sequel while racking your brain for ways to top the ending of this one.